1. Field of the Invention
The present general inventive concept generally relates to a method of measuring a paper size. More particularly, the present general inventive concept relates to an apparatus and method of measuring each size of sheets of paper loaded in a paper feeder of a body part of an image-forming apparatus.
2. Description of the Related Art
The image-forming apparatus outputs images appearing on monitors, television screens, and other image display devices. FIG. 1 is a view illustrating a paper feeder of an image-forming apparatus. Hereinafter, description will be made on operations between the paper feeder and the sheets of paper loaded in the paper feeder with reference to FIG. 1. The paper feeder includes a body part 100 for accommodating the sheets of paper loaded therein, and a fastener part 102 for fastening and preventing from movement paper loaded in the body portion. That is, the fastener part 102 moves to the left and right depending on a size of paper. The fastener part 102 moves to the right if the size of paper loaded in the body part 100 is narrow, and to the left if the size of paper loaded in the body part 100 is wide.
FIG. 2 is a view illustrating a structure A of the body part 100 of the image-forming apparatus, and FIG. 3 is a view illustrating a structure B of the fastener part 102 of the image-forming apparatus. Hereinafter, description will be made on the structure A of the body part 100 and the structure B of the fastener part 102 of the image-forming apparatus with reference to FIGS. 2 and 3.
The body part of FIG. 2 has first, second, and third contact parts 200, 202, and 204. The respective contact parts 200, 202, and 204 are extended by a certain length. The respective contact parts do not include one projection, but include at least two projections.
The first contact part 200 has the projections in the sections c, e, and f, and the second contact part 202 has the projections in the sections b, d, and f. The third contact part 204 has the projections in the sections a, d, and e. In other words, the section a has a readout of the third contact part 204, and the section b has the projection of the second contact part 202. The section c has the projection of the first contact part 200, and the section d has the projection of the second contact part 202 and the projection of the third contact part 204. The section e has the projection of the first contact part 200 and the projection of the third contact part 204, and the section f has the projection of the first contact part 200 and the projection of the second contact part 202. As described above, the image-forming apparatus has the projections different from section to section.
In FIG. 3 illustrating the structure B of the fastener part 102 of the image-forming apparatus, the fastener part 102 has the same number of sensors as the number of contact parts constituting the body part 100. Since FIG. 2 has three contact parts, the fastener part 102 also has three sensors. An interval between the sensors is equal to an interval between the contact parts. That is, the first sensor 300 contacts the first contact part 200, the second sensor 302 contacts the second contact part 202, and the third sensor 304 contacts the third contact part 204.
Hereinafter, description will be made on the measurement of the size of the paper loaded in the paper feeder using the projections of the body part and the sensors moving together with the faster part 102. As described above, the fastener part 102 is movable with respect to the body part 100, that is, can be adjusted depending on the size of the paper. If the sensors are positioned in the section a, the third sensor 304 detects the projection of the third contact part 204. If the sensors are positioned in the section b, the second sensor 302 detects the projection of the second contact part 202. If the sensors are positioned in the section c, the first sensor 300 detects the projection of the first contact part 200. If the sensors are positioned in the section d, the second sensor 302 detects the projection of the second contact part 202, and the third sensor 304 detects the projection of the third contact part 204. If the sensors are positioned in the section e, the first and third sensors 300 and 304 detect the projections of the first and third contact parts 200 and 204, respectively. If the sensors are positioned in the section f, the first sensor 300 detects the projection of the first contact part 200, and the second sensor 302 detects the projection of the second contact part 202.
The image-forming apparatus stores information on the number of detected projection(s) and the size of the paper depending upon their positions. Thus, the image-forming apparatus can recognize the size of the paper loaded in the paper feeder using a detection signal sent from the sensor(s).
However, the measurement of the paper size by a combination of the sensors causes a problem in that such measurement increases a volume of the body part and the fastener part for such detections. When the projections are damaged or a function of the projections deteriorates due to a temperature or a long-time use, it is impossible to perform precise detection through the damaged projections.